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   1  <?php
   2  /**
   3   * Native CDB file reader and writer.
   4   *
   5   * This program is free software; you can redistribute it and/or modify
   6   * it under the terms of the GNU General Public License as published by
   7   * the Free Software Foundation; either version 2 of the License, or
   8   * (at your option) any later version.
   9   *
  10   * This program is distributed in the hope that it will be useful,
  11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13   * GNU General Public License for more details.
  14   *
  15   * You should have received a copy of the GNU General Public License along
  16   * with this program; if not, write to the Free Software Foundation, Inc.,
  17   * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18   * http://www.gnu.org/copyleft/gpl.html
  19   *
  20   * @file
  21   */
  22  
  23  /**
  24   * Read from a CDB file.
  25   * Native and pure PHP implementations are provided.
  26   * http://cr.yp.to/cdb.html
  27   */
  28  abstract class CdbReader {
  29      /**
  30       * The file handle
  31       */
  32      protected $handle;
  33  
  34      /**
  35       * Open a file and return a subclass instance
  36       *
  37       * @param string $fileName
  38       *
  39       * @return CdbReader
  40       */
  41  	public static function open( $fileName ) {
  42          return self::haveExtension() ?
  43              new CdbReaderDBA( $fileName ) :
  44              new CdbReaderPHP( $fileName );
  45      }
  46  
  47      /**
  48       * Returns true if the native extension is available
  49       *
  50       * @return bool
  51       */
  52  	public static function haveExtension() {
  53          if ( !function_exists( 'dba_handlers' ) ) {
  54              return false;
  55          }
  56          $handlers = dba_handlers();
  57          if ( !in_array( 'cdb', $handlers ) || !in_array( 'cdb_make', $handlers ) ) {
  58              return false;
  59          }
  60  
  61          return true;
  62      }
  63  
  64      /**
  65       * Create the object and open the file
  66       *
  67       * @param string $fileName
  68       */
  69      abstract public function __construct( $fileName );
  70  
  71      /**
  72       * Close the file. Optional, you can just let the variable go out of scope.
  73       */
  74      abstract public function close();
  75  
  76      /**
  77       * Get a value with a given key. Only string values are supported.
  78       *
  79       * @param string $key
  80       */
  81      abstract public function get( $key );
  82  }
  83  
  84  /**
  85   * Write to a CDB file.
  86   * Native and pure PHP implementations are provided.
  87   */
  88  abstract class CdbWriter {
  89      /**
  90       * The file handle
  91       */
  92      protected $handle;
  93  
  94      /**
  95       * File we'll be writing to when we're done
  96       * @var string
  97       */
  98      protected $realFileName;
  99  
 100      /**
 101       * File we write to temporarily until we're done
 102       * @var string
 103       */
 104      protected $tmpFileName;
 105  
 106      /**
 107       * Open a writer and return a subclass instance.
 108       * The user must have write access to the directory, for temporary file creation.
 109       *
 110       * @param string $fileName
 111       *
 112       * @return CdbWriterDBA|CdbWriterPHP
 113       */
 114  	public static function open( $fileName ) {
 115          return CdbReader::haveExtension() ?
 116              new CdbWriterDBA( $fileName ) :
 117              new CdbWriterPHP( $fileName );
 118      }
 119  
 120      /**
 121       * Create the object and open the file
 122       *
 123       * @param string $fileName
 124       */
 125      abstract public function __construct( $fileName );
 126  
 127      /**
 128       * Set a key to a given value. The value will be converted to string.
 129       * @param string $key
 130       * @param string $value
 131       */
 132      abstract public function set( $key, $value );
 133  
 134      /**
 135       * Close the writer object. You should call this function before the object
 136       * goes out of scope, to write out the final hashtables.
 137       */
 138      abstract public function close();
 139  
 140      /**
 141       * If the object goes out of scope, close it for sanity
 142       */
 143  	public function __destruct() {
 144          if ( isset( $this->handle ) ) {
 145              $this->close();
 146          }
 147      }
 148  
 149      /**
 150       * Are we running on Windows?
 151       * @return bool
 152       */
 153  	protected function isWindows() {
 154          return substr( php_uname(), 0, 7 ) == 'Windows';
 155      }
 156  }
 157  
 158  /**
 159   * Exception for Cdb errors.
 160   * This explicitly doesn't subclass MWException to encourage reuse.
 161   */
 162  class CdbException extends Exception {
 163  }